To address new treatment approaches through AsthmaNet, National Jewish Health will contribute expertise under the direction of Drs. Richard Martin and Stanley Szefler along with experienced investigators from the ACRN and CARE Networks, and Dr. Lisa Cicutto as leader in the Education, Training and Career Development Core and the Community Engagement Core of the Colorado Clinical and Translational Sciences Institute. To understand the relationship of asthma, vitamin D deficiency and obesity in adults, we will examine the role of vitamin D supplementation to enhance inhaled corticosteroid (ICS) response. After a run-in period of ICS, based on evidence of vitamin D deficiency and stratified for body mass index, subjects with asthma, ages 18 to 70 years, will be randomized to ICS plus vitamin D or placebo for a 6-month period in a double-blind, parallel, placebo controlled design to evaluate change in asthma control. An associated mechanistic study will examine cellular mechanisms of steroid response related to the MAP kinase-1 pathway. To improve asthma management in young children, we will evaluate three treatments: low dose ICS delivered via nebulizer/face mask, low dose ICS via metered dose inhaler/spacer/face mask, or an oral leukotriene antagonist. After a placebo run-in, children with asthma, ages 1 to less than 5 years, will be randomized to one treatment in a double-blind, parallel design for a one-year study period. We will measure symptom control and exacerbations and also determine whether therapy can be individualized based on patient characteristics including biomarkers and genetics. To evaluate a novel treatment strategy, we will examine the role of an omega3/antioxidant nutritional formula on exercise-induced bronchospasm in adolescents, ages 12 to 18 years, using a double-blind, placebo controlled, parallel design over a three month treatment period. We will also implement a Clinical Research Skills Development Core Plan and contribute expertise in quality control of physiological clinical outcomes to develop independent academic clinical investigators in asthma. The National Jewish site will contribute collaborative experience, leadership skills and commitment for recruitment of adults and children to participate in AsthmaNet trials.